Aluminium plating.



UNTTED STATES ATENT OFFICE.

ANSON G. BETTS, OF LANSINGBURG, NEW YORK.

ALUMINIUM PLATING.

SPECIFICATION forming part of Letters Patent No. 675,584, dated time 4, 1901.

Application filed October 24, 1900.

To all whom, it may concern.-

Be it known that I, ANSON G. BETTS, a citizen of the United States, residing at Lansingburg, county of Rensselaer, and State of New York, have invented certain new and useful Improvements in Aluminium Plating, of which the following is a specification.

The principal object of my invention is to provide the surface of a body of aluminium or aluminium alloy with a permanently-adherent coating of some other metal, which metal is adapted to be electroplated, soldered, or tinned by some well-known method.

My invention consists in coating a body ofaluminium or aluminium alloy by bringing the surface to be coated into contact with a fused salt of the coating metal, as hereinafter more fully described,and particularly pointed out in the claims.

It is well known that aluminium surfaces cannot be successfully electroplated, and I believe that the firm and permanent attachment of a coating of another metal to aluminium by molecular contact has hitherto been unattained. The chief obstacle is probably the presence of aluminium oxid, which so readily and quickly forms on aluminium surfaces, a very slight amount of which would prevent a metallic union.

I make use of a combined fluxing and de: positing action removing the oxid from the aluminium surface to be coated and preparing a clean free metallic surface to receive the deposit of the coating metal. I also make use of a high temperature, which insures the absence of water and prevents the formation from water of hydrogen simultaneously with the reduction of' the salt to metal by the chemical action of the aluminium.

In carrying out my process I provide a comparativelydry salt of the metal with which it is desired to coat the body of aluminium and heat the same to a condition of fusion. The fused salt being brought into contact with the aluminium surface to be coated the metal contained in the fused salt exchanges with the aluminium and is evenly deposited by chemical action upon the contact-surface of the aluminium.

For example, if a thin layer of dry ouprous chlorid is placed, as by a sifter, upon a sheet of aluminium and heat applied sufficient to Serial No. 84 195- (Nb specimens.)

fuse the salt without fusing the aluminium the fused salt spreads out evenly and the copper is deposited by chemical action; The appearance of white fumes of aluminium chlorid or oxychlorid shows that chemical reaction is taking place. The semifused resulting salts are easily removed by scraping while still hot. The aluminium sheet may be coated on the opposite side or not, as desired. The coating applibd as above described may be reinforced or made thicker by electrodeposition or by dipping in any of the well-known methods.

It is obvious that the aluminium body to be coated can be dipped in a receptacle con taining the fused salt of the coating metal or the fused salt applied in any known manner.

The failure to successfully electroplate aluminium by the usual means of electroplating metals results from the fact that anhydrous aluminium oxid, which always forms on the surface of aluminium, even though in a slight degree, is insoluble in any aqueous plating solution, whether acid or basic. The interposition of a layer of aluminium oxid, however thin, prevents metallic uniou. Thesuccess of this process depends on the solvent etfect on the oxid of fused metallic salts, particularly salts of the more basic metals, like copper.

The higher temperature used is an advantage, because it tends to promote alloying at the junction of the two metals.

The surface of the aluminium body to be coated or plated may be immersed in a bath of a fused salt of the coating metal and when desired the plating action made continuous by inserting in the same bath a piece of the coating metal and connecting the aluminium as cathode and the piece of coating metal as anode with a source of electric energy in the well-known manner of electroplating.

By the word aluminium I desire to include all alloys of aluminium which cannot be successfully coated or plated by previously-known methods.

After the aluminium surface has been provided with a thin coating of some metal, as copper, that coating may afterward be reinforced in any manner, as by electrodepositing or fusing some metal thereon.

I prefer the use of a non-oxygen salt of the treating an aluminium surface with aluminium with other metals which consists in treating an aluminium surface with a fused coating metal, such as haloid copper salts, and more particularly cuprous salts as distinguished from cupric salts, by the use of which I find it unnecessary to employ a horacic or other flux tofacilitate fusiouand avoid the formation of oxide and insure the solution of any oxide which may be present.

The haloid salts, which are preferably employed in my process, are those in the lowest form of oxidation or combination.

What I claim as new, and desire to secure by Letters Patent, is-

1. That improvement in the art of coating non-oxygen salt of a coating metal capable itself of dissolving aluminium oxid and capable of being reduced to a metallic state by the action of aluminium.

2. That improvement in the'art of coating aluminium with other metals which consists in treating analuminium surface with a fused non-oxygen haloid salt of a coating metal in the lowest form of oxidation, capable of dissolving aluminium oxid and of being reduced to a metallic state by aluminium.

8. That'improvement in the art of coating aluminium with copper which consists in treating an aluminium surface with a fused non-oxygen copper salt.

4. That improvement in the art of coating aluminium with copper which consists in a fused non-oxygen cuprous salt.

5. That improvement in the art of coating I aluminium with copper which consists in treating an aluminium surface with fused cuprous chlorid.

6. That improvement in the art of coating aluminium with another metal which consists 40.

in placing on the surface to be coated a layer of dry, fusible, non-oxygen salt of a coating metal capable itself of dissolving aluminium oxid, and capable of being reduced to a metallie state by the action of aluminium, and '45 heating the whole until such salt is fused and the coating efiected by the action of the aluminium on the fused metallic salt, substantially as described.

7. That improvement in the art of coating 50' aluminium with copper which consists in placing on the surface to be coated a layer of cuprous chlorid and heating the whole until said cuprous chlorid is fused and the surface has been evenly coated with copper by the 55 7 action of the aluminium on the fused copper salt, substantially as described.

8. Thatimprovement in the art of coating aluminium with another metal which consists in treating the surface to be coated with fused 6o Anson G. BETTS.

Witnesses:

GEO. A. Mosrma,

FRANK O. CURTIS. 

